Translating device



Oct. 31, 1933. E W GENT TRANSLATING DEVICE Filed Feb. 27, 1931 2 Sheets-Sheet 1 MMM Arron/v51( Y Oct. 31, 1933. E- w. GENT 1,933,252

TRANSLATING DEVI CE Filed Feb. 27, 19.51 2 Sheets-Sheet 2 /NVENTOH E. W GENT BY ATTORNEY Patented Oct. 31, 1933 y TRANSLATING DEYICE A `Edgar Gent, Morristowm'N.v J., Vassi'gnor `to Bell Telephone Laboratories, Incorporated;

New York, N. Y., a corporation of NewYork y Application February 2,7, 1931. ,serial No. 518,742

9` ciaims." f (o1. zas-61) This invention relates to' translating devices and particularly to lightvalves used'forrecordking sound on a rphotograplfiic' medium.r

The objects are to simplify the construction of i light valves by reducing'the sizeand number of parts involved, to facilitate accurate adjustment of the vibratory elements'to safeguard the device from losing its adjustment due to temperature changes, andto otherwise improve lapparatus of this character. y

It has been proposed "heretofore to mount the vibratory strings or ribbons of vthe light'valve on suspension bridges and to adjust them with respect to each other and with respect toa lighttransmitting apertureby means of adjusting ele'- ments which engage the ribbons `at points adjacent to the points of suspensionon the bridges,` These adjusting elements, 1 consisting of microm` eter screws, together with the bridges' involve `a considerable amounty of material whichis subject to expansion and contraction due to temper-l ature changes.` This variation rdue to temperature is likely to disturb the proper adjustment of the ribbons. Moreover, itfis difficult to obtain a' proper adjustment of the ribbons dueto'the fact that the adjusting elements engage these ribbons at points somewhat removed from the bridge sus pension points. f

`According to the present invention theseob-l jections are overcome by means of a light valve in which the suspension ybridgesA on which the vibratory ribbons are supported are adjustable by means of micrometer screws.' This enables the adjustment to be made exactly at the points of suspension of the ribbons. Also, since adjustment takesjplace atthe'po'int of suspension,I it is possible to considerably reduce the `amount of material involved in the supportingand-adjusting A parts. `This, in turn, lessens the' variationdue to temperature changes.

This invention hasI been illustrated in the accompanying drawings in which, Fig. 1 shows a light valve partly in section which embodies the features of this invention; Fig. 2 shows in perspective the bridges that support the vibratory strings or ribbons and a portion of the pole` piece over which these ribbons are suspended; Fig. 3 is a plan view of the interior of the casing cover shown in Fig. 1. 4This figure shows the complete suspension means for the ribbons and the associated pole piece as mounted on the cover; and Fig. 4 is a side View of` this cover partly in section along the line 4`4 of Fig. 3.

`The general structure of this light valve may be along the line disclosed in the patent of E. W.

Gent er1-a1 No. 1,352,774,111ed January 31, 1929,` granted, April 5, 1932. The principle of operation of light valves of this classis disclosed in the"v patent toE. C. Wente No. 1,638,555 of August 9,A 1927. Referring to Fig. 1 the valve consistsI ci aI casing 1 having a cover 2 secured toY this casingY by ring 3:v The casing 1 contains an electro-magnet comprising a winding 4 and core 5@ To thisy core r5 is secured a pole piece 6, while on the cover 2 is mounted a pole piece 7 and the ribbonkk suspension? means shown in full detail in Fig. 3. l

' Referring now particularly to Figs. v3 andf-i.' it

will be seen ythat one end of the ribbon 10 is:k

secured to a takeupscrew `11 and from there it` is drawn across the pole piece 7 over the lighttransmitting aperture 12 therein, passed aroundY an idler pulley 13, back againover thepole piece 7 and' terminating at the take-upscrew 14. V The take-up screwsll and 14 are mounted on blocksY 16 and 17, respectively. These blocks are secured side of 'the cover 2. *Sound modulated current may therefore be supplied to the ribbon 10 through thse binding The pulley 131s mounted in the spring sus#y pension' device 22A whichis'secured to the cover 2. This device may be adjustable fromvthe 'front' of thercover 2, bymeans of a tapered screw sur# roundedby the guard 23, to regulate the tension on thevribbon 10.

` To obtain accurate and reliable operation on the part of the ribbonthe two portions thereof must-be 'in exact space relation to each other' and be-,in alignment across the face of the pole piece andthe aperture 12. To this end there is provided means whereby thefribbon is adjusted at the bridgeasuspension points at opposite'sides of the'pole piecesf7 independently. This means consists of a bridge block 24 for each susperlby sion point.v Each of these bridge blocks'`v 241s secured by means of screws or other means to the cover 2 and consists of a projection 25, which is made flexible in relation to a projection 26 of the block 24 by means of a saw slot 27. This projection 25 may be adjusted in relation to projection 26 by a micromatic screw 29 threaded into projection 26. On the projection 25 is mounted an ivory strip`30 riveted thereto in any suitable manner and at the top of this strip is mounted a pin 31 in such a position that the ribbon may rest on the. ivory strip and against the inner surface of the pin 31'. `By means of the screws 29 the projections 25 may be slightly moved to adjust the ribbon at the suspension points in proper relation to the aperture 12, and the two portions of the ribbons suspended over the aperture may therefore also be adjusted in proper relation to each other. It is readily seen that this adjusting means comprising the bridge blocks 24, bridge projections 25 and 26 and screws 29 as well as the ivory strips 30 may be made comparatively small and therefore n'ot materially 1. The combination in a translating device of a mounting member, an element secured to said member and having a light-transmitting aperture therein, a bridge member secured to said mount'- ing member, a vibratory string attached to the mounting member and suspended by saidV bridge to define the opening throughr said aperture, and means for moving said bridge with respectto the mounting member to effect an adjustment ofsaid string. c 2. The combination in a, translatingdevice of a mounting plate, an element secured to said plate and having a `light-transmitting aperture therein, a pair of bridges secured to said mounting plate, a vibratory ribbon attached to the mounting platel and suspended by said bridges to define the opening through said aperture, and means for moving said bridges to effect an adjustment of said ribbon with respect to said aperture. v

3. The combination in alight valve of a mounting plate, a member thereonhaving a light-transmitting slot therein, a pair of bridges seuredto said mounting plate, `a. vibratory ribbon secured to said mounting plate and suspended by said bridges to define theopening through said slot,`

locking pins on said bridges for holding said ribbon in position thereon, and adjusting meansfvor moving said bridges to adjust the position of said ribbon with respect to said slot.

4. The combination in a translating device of a mounting plate,y a pair of pole piecesV having coaxial light-transmitting slots therein, one of said pole pieces secured to saidmounting plate, two bridges secured to said mounting plate, one

on either side of said last mentioned pole piece, a

vibratory ribbon attached to said mounting plate and having two portions suspended by said bridges to define the opening through said slot, and means for adjusting said bridges to shift the position of said portions with respect to said slot.

5. The combination in a light valve of a mountl said aperture.

ing plate, an element thereon having a lighttransmitting slot, a pair of bridges secured to said plate, a vibratory ribbon attached to said plate and having two portions suspended by said bridges to define the opening through said slot. means for adjusting the tension of said ribbon, locking pins in said bridges for retainingv said portions in position with respect to said slot, and adjusting means for moving said bridges to shift the position of said portions with respect to said slot. f

6. The combination in a light valve of a mounting plate, a member having a light-transmitting slotfand secured to said plate, two bridges attached to said plate, each bridge consisting of two parts located adjacent to each other, a vibratory ribbon attached to said plate and having two portions suspended by `said bridges to define the `opening through said light-transmitting slot, and

`aligned magnetssupported by said frame, said magnets having aligned apertures, suspension members fixedly secured to said frame, an electrical conductor suspended by said members between the adjacent faces of said magnets and traversing the ends of said apertures to define a light-transmitting slot, each of said suspension members being slotted soas to render the suspending extremity'slightly flexible with respect to the `fixed portion of said member, and screw` means cooperating between the fixed and iiexible portions of said membersfor adjusting the position of said conductor with respect to said apertures. Y v e 8. Inalight valve,a frame, amember supported by said `frame and having a light-transmitting slot therein, a vibratory ribbon for defining the 1 opening through said slot, blocks securely iixed to said frame for suspending said ribbon across the end of said slot, the suspending extremity of each. block being slightly fiexible, and means engaging theexible portion of eachk block for adjust- -1 ing the positionV of said ribbon with respect to 9. The combination in a light valve of a mounting plate, a member secured to said plate and having a light-transmitting slot therein, a rib- 1 bon carrying an electrical current and attached to saidA mounting plate to form a loop having its two parallel portions traverse said slot to define the opening through which light may pass, blocks affixed to said .plate for suspending said parallel 1 portions of the ribbon and formed so that the ribbon supporting portions are slightly iiexible, and screws engaging the fixed and ilexible portions of said blocks for making a fine lateral adjustment of said ribbon with respect tosaid slot. 1

EDGAR W. GENT.

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